The objective of this research is to elucidate fundamental processes for circulation in oral tissues to obtain additional knowledge of basic cardiovascular physiology relative to dentistry. The ongoing projects involve assessing of methodology, establishing animal models for observing circulation following maxillary and mandibular osteotomies, evaluating regulatory factors of the circulation and developing various theoretical models, as well as expanding our on-line computer capabilities. More specifically, investigations will be carried out to examine the circulatory changes, the role of collateral circulation to tissues and related fundamental processes in restoring homeostasis following the experimental procedures. The isotope fractionation technique using Rb 86 and/or particle distribution method using radioactive microspheres will provide quantitative values of blood flow in various tissues. These methods will be combined with others, such as fiberoptic densitometry an some studies, thus providing further description of the physiological processes. These projects may define methods which can have clinical application.